Boiler wall



April Il 16, Ylil-)29.

r. E. MURRAY BoILER WALL Filed Maron 2s. 19?

' I N VENTOR foMAsfM/RHAH /MMMA TTORNE'Y ,cent to the fastened to eachother and to by flanges 4 on their vertical edges embedded Y provided by means of tiles Patented Apr. 16, 1929.

UNITED STATES.

THOMAS E. MURRAY, 0F BROOKLYN, NEW YORK.

BOILER WALL.

Application inea Maren 23,1927'. serial No. 177,533.

My invention aims to provide an improved wall structure for boiler furnaces operating at very high temperatures, and particularly for furnaces fired like.

lFig. 1 is an inside face elevation of a wall;

lFig. 2 is a cross-section of the same;

A 4hg.' 3 is a cross-section in detail showing the wall as originally built;

Fig. 4 is a view similar to Fig. 1 illustrating a modification.

Referring to theconstruction illustrated, the principal part of the structure is a wall 1 of brick-work or similar refractory material commonly used for this class of Work, having any usual or suitable hard finish layer 2 on the outer face. 0n the inner face of the brick-work it is Afaced with metal plates 8 which arepreferably highly resistant to oxidation at high temperatures. The plates are the brick-work in the brick-work. -On the inner face of the plates 3 is a coating 5 of pQwdeI-.y or granular material of mineral or similar composition which saves the plates from excessive heat. The plates 3 may be further tied to the brickwork by tongues 6 bent back from the plates and embedded in the brick-work.

In front of the structure thus described,

-and which may be referred to as a whole as a refractory Wall, is a row of.vertical tubes 7 carrying water which is circulated upward at a high rate of speed; thesetubes belng con- ,nected into a boiler circulation of any suitable type.

The burning fuelproduces an intense heat which is radiated directlyagainst the tubes 7 and, between these tubes, against the refractory wall.l The tubes, with the water in them, create a comparatively cool zone adjaplates 3. This, and the mineral coating 5 protect the plates so that they will be durable even under extreme conditions. n

Further protection for the plates may be mg divided along a central line to engage a A. portion `9 of reduced cross-section, to hold the tiles 'in place.

register with` the spaces between the tubes, -where the direct el'ectof the radiantheat is greatest.

The same arrangement Iof ntiles 8 maybe made in line with the spaces between each pairA of tubes 7. The furnace is designed .particularly for operating at high temperawith powdered coal or the f 8, each plate 3 be- These tiles are located in i scribed will tures, such as are obtainable by use of powdercd coal or other`fuel introduced through jet nozzles. lhe high temperature will produce a certain expansion o1 the plates 3 and of the brick-work l behind theln. The ex- .pansion will be approximately the same inv the vertical direction, or so nearly so as not to present any dilliculty.

To allow for lateral expansion, the'flangcs of the plates 3, when they are built up cold, should be of the converging shape shown ,at Pl Fig. 3, leaving a slight space so that when the furnace is heated, the plates may come together in the manner indicated in Fig. 2. Such expansion joints are not claimed in the present application, being covered, with cerof the tubes, and more tain arrangements fully illustrated it my co-pending applica- March 14, 1928.

tion No. 261,493 filed 8 covering joints in the The overlapping plates` 10 are all of material resistant to' high temperature, such as Stellite or similar grades of steel. ll1ey 'may be spaced apart as in Fig. 4 so-as to secure only partial protection, or they may extend continuously from top to bottom of the joint so as to entirely cover the latter. They can be fastened to the plates 3 by welding or otherwise.

'1n the operation of furnaces of this class, particularly -with `coal dust firing, the cold metal plates 3 are found to accumulate a deposit of powdery or granular mineral matter,-

which adheres very lightly so that it can be knocked off or brushed oi with ease. This incidental deposit serves two very useful functions. It protects the steel platesfrom burning. It is also heated to incandescence or similar high temperature so as to present a highly heated surface to the gases. This is important, particularly with low grades of coal, to protect the gases from'the excessive cooling eli'ect such as might be providedl by the metal plates and thus to better the combustion and diminish the smoke. f 'A Such a coating will build up only td a slight thickness, sufficient to maintain a certain balance of heatI abstracted from theflame.

- -The building of the wall in the manner decoating in a brief period after the furnace is putin service. I may, however, provide what I call a permanent 'coating to distinguish it ensure the existence of such` a from the incidental or automatic coating described. This can be done by painting or spraying the steel plates With a sticky carbonaceous material which will be furthericoated with the mineral deposit in actual use; o r by l applying at once a coating 'of the fullithickness desired which will not build up -toany substantial extent.

The greatest heat reaches the portions of the Wall which are in line With the spacesbetween the tubes, and the metal lining maybe made to cover only these portions of the brick-work or similar refractory material, leaving the latter bare immediately behind the several tubes.

The Wall described, of brick Work or the like 'is the usual type of boiler Wall, which is generally self supporting and often carries part of the Weight of the overhead structure.

It is to be distinguished from a mere layer or sheathing of insulating material such as is shown for example in my British Patent No.

227,156 of 1924 which is held in place by embedded Woven Wire secured to and supported from the plates and tubes, the latter constituting the primary support.

Various modifications may be made by those skilled in the art Without departing from the invention as defined in the following claims.

Vhat I claim is 1. A boiler furnace wall comprising a backing of refractory material With metal plates on its inner face in combination with a line of vertical water tubes spaced apart from each otherandadjacent to but spaced apart from the face of the Wall on the furnace side thereof and serving to protectit partially from the radiant heat of the burning fuel.

l 2. A boiler furnace Wall comprising a backing of refractory material with metal plates on its inner face and a mineral coating on the faces of said metal plates in combination with .a line of vertical Water tubes spaced apart from each other and adjacent to but spaced apart from the face of the Wall on the furnace side thereof and 'serving to protect'it partially from the radiant heat of the burning fuel.

3. `A boiler furnace Wall havingv a backing Vof refractory material in combination with a line of vertical Water tubes spaced apart from ,each other and adjacent to but spaced apart from sai'd Wall and high temperature resistant backing of refractory material with a 'metal inner face in combination With Water tubes spaced apart from each other, the metal face. of the wall being composed of plates extending continuously behind the tubes and being partially protected by said tubes from the radiant heat of the burning fuel and high temperature resistant protective means on the face of the wall in line with the space between the tubes.

6.- A boiler-furnace Wall comprising a backing of refractory material with a metal inner face having a mineral coating, in combination with Water tubes located adjacent to and on lthe furnace side of said metaf face and protectingit from the direct radiant heat of the burning fuel.

In Witness whereof, I have hereunto signed my name. v Y

7 THOMAS E. MURRAY. 

